Tire hardness tester

Abstract

An apparatus for gauging the hardness of tire treads wherein a support member moveable supports a durometer which is connected to means for controlling the rate of descent of such a durometer to provide a constant predetermined force for measuring the hardness of a tire tread. A tire support supports a tire such that it is in alignment with the durometer.

We claim: 
     
       1. An apparatus for gauging the hardness of tire treads comprising a support, said support having bracket means at the upper end thereof, a durometer support means mounted on said bracket means, a durometer mounted on said support means for vertical movement, said durometer having a penetrator for contact with a tire tread to provide a hardness reading on said durometer, control means mounted on said durometer support means and operatively connected to said durometer for controlling the movement of said durometer at a uniform rate of descent, a tire support means connected to said intermediate portion of said support for presenting an upper tread portion to said durometer, and said tire support means having a tread support member located on the inner peripheral surface of a tire in alignment with said penetrator of said durometer. 
     
     
       2. An apparatus for gauging the hardness of tire treads as set forth in claim 1 wherein said control means includes a dashpot connected to said durometer to control the descent of said durometer. 
     
     
       3. An apparatus for gauging the hardness of tire treads as set forth in claim 2 wherein said tire support means has a plurality of rollers for rotatable supporting said tire to provide means for presenting different portions of a tire tread to said durometer. 
     
     
       4. An apparatus for gauging the hardness of tire treads as set forth in claim 1 wherein said control means includes a plunger with a rack thereon, said rack meshing with a rotatable gear journaled on said support means, said control means includes a dashpot mounted interconnected to said plunger and said durometer to control the vertical movement thereof, and lock means connected to said plunger to control the limits of movement of said plunger and durometer. 
     
     
       5. An apparatus for gauging the hardness of tire treads as set forth in claim 4 wherein said lock means includes a lever pivotably mounted on said support means, and a cam connected to said gear for rotation therewith and for contact with said lever. 
     
     
       6. An apparatus for gauging the hardness of tire treads as set forth in claim 5 wherein said tire support means includes a plurality of rollers for supporting a tire, and one of said rollers being located in alignment with said penetrator and operative to frictionally contact the inner periphery of said tire. 
     
     
       7. An apparatus for gauging the hardness of tire treads as set forth in claim 6 wherein said durometer support means is pivotally connected to said bracket means and operative to swing said durometer support means away from said tire support means. 
     
     
       8. An apparatus for gauging the hardness of tire treads as set forth in claim 7 wherein said tire support means had an adjustable member for extension downwardly and laterally to contact the lower inner periphery of a tire to stabilize a tire on said tire support means. 
     
     
       9. An apparatus for gauging the hardness of tire treads as set forth in claim 8 wherein said plurality of rollers include at least a pair of laterally spaced adjustable rollers operative to support a tire for rotation thereon to present different portions of the tire tread surface to said penetrator. 
     
     
       10. An apparatus for gauging the hardness of tire treads, a support member, tire support means mounted on said support member for supporting the upper inner circumferential surface of a tire, said tire support means having lower longitudinally extending mounted thereof for adjustment downwardly and laterally for contact with the lower inner periphery of a tire to stabilize a tire thereon, a durometer support member mounted on said support member, said durometer support member having a housing thereon, a dashpot mounted on said durometer support member, a durometer with a penetrator mounted on said durometer support member for movement toward and away from the surface of a tire tread supported by said tire support means, and means interconnecting said dashpot and said durometer to control the uniform descent of said durometer and said penetrator. 
     
     
       11. An apparatus as set forth in claim 10 wherein said housing guides a reciprocal plunger connected to said means interconnecting said dashpot and said durometer for movement therewith, said housing has a gear journaled therein, said plunger having a gear rack meshing with said rotatable gear, and pawl means connected to said gear to limit the vertical and downward movement of said plunger and durometer. 
     
     
       12. An apparatus as set forth in claim 11 wherein a light beam source is mounted on said support member and projects and image on a tire tread at the exact location that said penetrator will contact said tread.